Aqueous coating substance that can be cured physically, thermally or thermally and by using actinic radiation and use thereof

ABSTRACT

A solventborne coating material curable physically, thermally, or thermally and with actinic radiation, comprising  
     A) at least one binder curable physically, thermally, or thermally and with actinic radiation,  
     B) at least one color and/or effect pigment, and  
     C) at least one colorless, transparent or opaque powder which is substantially inert with respect to the other constituents of the coating material and whose particles have an average size of from 1.0 to 10.0 μm and a density of from  1.25  to  3.6  g cm −3    
     and its use as basecoat material for producing multicoat color and/or effect paint systems.

[0001] The present invention relates to a novel solventborne coatingmaterial and to its use for producing single-coat and multicoat colorand/or effect paint systems in automotive OEM finishing and automotiverefinish, in industrial coating, including coil coating and containercoating, in the coating of plastics, and in furniture coating.

[0002] Solventborne coating materials curable physically, thermally, orthermally and with actinic radiation have been known for a long time.These known solventborne coating materials, especially the basecoatmaterials, and the single-coat or multicoat color and/or effect paintsystems produced with them possess very good performance properties.

[0003] Where the single-coat or multicoat color and effect paint systemsproduced from the known solventborne coating materials comprise effectpigments, especially metallic pigments, there may be formation of whatare known as clouds, i.e., areas of light/dark shading. These are anindicator of deficiencies in dispersing and/or orienting the colorand/or effect pigments, especially the effect pigments, in the finish.However, it is precisely in the case of particularly high-value productshaving extensive finishes, such as automobiles, for example, that cloudyfinishes are fundamentally unacceptable, since paint defects of thiskind suggest low quality in the entire product (e.g., the automobile).

[0004] Clouding occurs in particular in color and effect paint systemswhich have bright metallic shades. The clouding is dependent on the coatthickness and wetness, and therefore occurs to an increased extent inthe overlap zones of the paint jets produced by the atomizers.

[0005] Moreover, when the known solventborne coating materials are usedfor refinish, unacceptable differences in shade arise between theoriginal finish and the refinish when one and the same basecoat materialis used. The reason for these unwanted shade differences arising isprimarily that the original basecoat is applied by electrostaticspraying, or by electrostatic spraying and pneumatically, whereas therefinish is applied pneumatically alone.

[0006] The American patent U.S. Pat. No. 4,652,470 A discloses awet-on-wet technique for producing multicoat color and/or effect paintsystems, in which the solventborne basecoat material comprises insolublepolymer microparticles having a diameter of from 0.01 to 40 μm. In orderto prevent strike-in of the clearcoat into the basecoat, the clearcoatmaterials must comprise inorganic microparticles with a size of from 1to 150 nm.

[0007] The German patent application DE 100 04 494.8, unpublished at thepriority date of the present specification, describes an aqueous coatingmaterial curable physically or thermally and/or with actinic radiationand comprising

[0008] A) at least one ionically and/or nonionically stabilizedpolyurethane which is saturated, unsaturated and/or grafted witholefinically unsaturated compounds, as binder,

[0009] B) at least one color and/or effect pigment, and

[0010] C) at least one colorless, transparent or opaque powder which issubstantially inert with respect to the other constituents of thecoating material and whose particles have an average size of from 1.0 to10.0 μm and a density of from 0.8 to 3.6 g cm⁻³.

[0011] The aqueous coating material produces aqueous basecoats in whichclouding is minimal.

[0012] It is an object of the present invention to provide a novelsolventborne coating material which is curable physically, thermally, orthermally and with actinic radiation and which is very highly suitableas a basecoat at material or solid-color topcoat material for producingsingle-coat and multicoat color and effect paint systems which exhibitmarkedly reduced clouding.

[0013] The color and effect paint systems produced using the novelsolventborne coating materials should have improved shade stability inresponse to changes in coat thickness and/or wetness. Moreover, theshade of original finishes and refinishes should match when one and thesame solventborne basecoat material is used.

[0014] The invention accordingly provides the novel solventborne coatingmaterial curable physically, thermally, or thermally and with actinicradiation, which comprises

[0015] A) at least one binder curable physically, thermally, orthermally and with actinic radiation,

[0016] B) at least one color and/or effect pigment, and

[0017] C) at least one colorless, transparent or opaque powder which issubstantially inert with respect to the other constituents of thecoating material and whose particles have an average size of from 1.0 to10.0 μm and a density of from 1.25 to 3.6 g cm⁻³

[0018] and is referred to below as the “coating material of theinvention”.

[0019] Further subject matter of the invention will emerge from thefollowing description.

[0020] In the light of the prior art it was surprising and unforeseeablefor the skilled worker that the object on which the present invention isbased could be achieved by means of the specially selected powder (C)for use in accordance with the invention. Indeed, the expectation wasmore that the use of powders (C) whose average particle size lies withinthe order of magnitude of the dry film thickness of the basecoats orsolid-color topcoats produced from the coating materials of theinvention would be accompanied by serious disadvantages, especially withregard to the quality of the overall appearance and the level ofintercoat adhesion. Moreover, it was surprising that there was no shadedifference, or only a very low, acceptable shade difference, when abasecoat produced from the coating material of the invention wasrefinished with one and the same coating material of the invention.

[0021] The coating material of the invention may be physically curing.

[0022] In the context of the present invention, the term “physicalcuring” denotes the curing of a layer of a coating material by filmingthrough loss of solvent from the coating material, with linking withinthe coating taking place via looping of the polymer molecules of thebinders (regarding the term, cf. Römpp Lexikon Lacke und Druckfarben,Georg Thieme Verlag, Stuttgart, New York, 1998, “binders”, pages 73 and74). Or else filming takes place by way of the coalescence of binderparticles (cf. Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag,Stuttgart, New York, 1998, “curing”, pages 274 and 275). Normally, nocrosslinking agents are required for this purpose. Where appropriatephysical curing may be assisted by atmospheric oxygen, by heat or byexposure to actinic radiation.

[0023] The coating material of the invention may be thermally curable.In this context it may be self-crosslinking or externally crosslinking.

[0024] In the context of the present invention, the term“self-crosslinking” refers to the capacity of a binder to enter intocrosslinking reactions with itself. A prerequisite for this is that thebinders already contain both kinds of complementary reactive functionalgroups which are necessary for crosslinking, or else the binder containsreactive functional groups which are able to react “with themselves”.Externally crosslinking coating materials, adhesives and sealingcompounds, on the other hand, are those in which one kind of thecomplementary reactive functional groups is present in the binder andthe other kind is present in a curing or crosslinking agent. For furtherdetails, refer to Römpp Lexikon Lacke und Druckfarben, Georg ThiemeVerlag, Stuttgart, New York, 1998, “curing”, pages 274 to 276,especially page 275, bottom.

[0025] The coating material of the invention may be curable thermallyand with actinic radiation. Where thermal curing and curing with actinicradiation are employed together in the context of one coating material,the terms “dual cure” and “dual-cure coating material” are also used.

[0026] In the context of the present invention, actinic radiation meanselectromagnetic radiation, such as near infrared (NIR), visible light,UV radiation or X-rays, especially UV radiation, and corpuscularradiation, such as electron beams.

[0027] The coating material of the invention may be a one-component (1K)system.

[0028] In the context of the present invention a one-component (1K)system is a coating material curable thermally or thermally and withactinic radiation in which the binder and the crosslinking agent arepresent alongside one another, i.e., in one component. A prerequisitefor this is that the two constituents crosslink with one another only atrelatively high temperatures and/or on exposure to actinic radiation.

[0029] The coating material of the invention may also be a two-component(2K) or multicomponent (3K, 4K) system.

[0030] In the context of the present invention, this means a coatingmaterial in which in particular the binder and the crosslinking agentare present separately from one another in at least two components whichare not combined until shortly before application. This form is chosenwhen binder and crosslinking agent react with one another even at roomtemperature. Coating materials of this kind are employed in particularfor coating thermally sensitive substrates, especially in automotiverefinish.

[0031] The coating material of the invention is solventborne. This meansthat its constituents are present in dispersion and/or solution in atleast one organic solvent.

[0032] The essential constituent of the coating material of theinvention is the powder (C). This powder (C) is a powder of uniformcomposition, i.e., its particles materially have the same composition.Or else it is a mixture of at least two powders (C). The decision as towhich variant is given preference is guided by the requirements whichare imposed on the coating material of the invention in the case inhand. In the great majority of cases, the use of one powder (C) issufficient to achieve the advantages according to the invention.

[0033] The powder (C) for use in accordance with the invention iscolorless. This means that it has no hue and no chroma but onlylightness. Accordingly, it is white or has a gray shade. Preferably,however, it is white. For further details, refer to Römpp Lexikon Lackeund Druckfarben, Georg Thieme Verlag, Stuttgart, New York, 1998,“achromatic point”, page 590.

[0034] The powder (C) is transparent in the sense of clear or opaque inthe sense of hiding. Preference is given to using transparent powders(C).

[0035] The powder (C) is substantially inert. This means that, withinthe period of time commonly envisaged for the preparation, storage, andprocessing of the coating material of the invention it is soluble onlysparingly if at all in the organic solvents present in the coatingmaterial of the invention, does not absorb any major constituents of thecoating material or cause them to flocculate, does not enter into anychemical reactions, or enters into only very slowly proceeding chemicalreactions, with essential constituents of the coating material, does notcatalyze any chemical reactions between the essential constituents ofthe coating material, and is unaltered, or altered only very slowly, inits properties by heat and/or actinic light.

[0036] The powder (C) has an average particle size of from 1.0 to 10.0,preferably from 3.0 to 7.5, and in particular from 4.0 to 7.0 μm.

[0037] Advantageous powders (C) have a comparatively narrow particlesize distribution. In other words, the fractions both of fine materialand of coarse material are comparatively low. Particularly advantageouspowders (C) have a maximum particle size of below 12, preferably below11 and in particular below 10 μm.

[0038] The particles of the powder (C) for use in accordance with theinvention have a density of from 1.25 to 3.6, preferably from 1.3 to3.4, more preferably from 1.35 to 3.2, and in particular from 1.4 to 3.0g cm⁻³.

[0039] In certain cases it also possible to use particles having ahigher density; in that case, however, the risk exists of the particlessettling fairly rapidly on prolonged storage.

[0040] The particles of the powders (C) for use in accordance with theinvention may be of any desired shape. In accordance with the inventionit is of advantage if they have a spherical shape. In the context of thepresent invention, a spherical shape is a shape substantially like thatof a ball. Examples of spherical shapes are beads, egg-shaped particles,dodecahedra or icosahedra, which may also have certain irregularities.

[0041] Examples of suitable substances of which the particles or powders(C) may consist are crosslinked or uncrosslinked organometallicpolymers, inorganic minerals, salts or ceramic materials, or organicallymodified ceramic materials, or mixtures of these substances. Of these,the inorganic minerals are of advantage and are therefore used withpreference. These minerals may be natural minerals or syntheticminerals.

[0042] Examples of the highly suitable minerals are silicon dioxide,aluminum silicates, calcium silicates, magnesium silicates, calciumaluminum silicates, magnesium aluminum silicates, calcium magnesiumsilicates, calcium magnesium aluminum silicates, beryllium aluminumsilicates, aluminum phosphate or calcium phosphate, or mixtures thereof.Of these, silicon dioxide is particularly advantageous and is thereforeused with particular preference in accordance with the invention.

[0043] The preparation of the powders (C) for use in accordance with theinvention has no special features in terms of its method but insteadtakes place with the aid of methods such as customary and known in thefield of organometallic or inorganic chemistry. For example,organometallic polymer particles may be produced by size reduction,preferably by grinding or spraying, of melts or solutions ofready-produced organometallic polymers. The inorganic particles may beproduced, for example, by precipitation processes and/or size reduction.In the case of ceramic materials, it is normal first to produce a greenbody, which may already have the desired powder form, and then to fireit.

[0044] Where appropriate, the surfaces of the particles are subjected toan aftertreatment, for example, to a hydrophilicizing orhydrophobicizing treatment. However, the aftertreatment must not removethe inertness of the particles.

[0045] The powders (C) may be incorporated as they are into the coatingmaterials of the invention, provided they are readily dispersed and donot agglomerate. In accordance with the invention it is of advantage ifthe powders (C) are incorporated in the form of powder pastes. Furtheradvantages result if the paste resins or grinding resins used comprisebinders which are present in the coating material of the invention.

[0046] The amount of the powders (C) in the coating materials of theinvention may vary very widely and is guided primarily by the intensityof the light/dark shading that is to be avoided and by the specifiedshade of the color and effect coating which is produced from therespective coating material of the invention. It is preferred to employfrom 0.05 to 7.0%, more preferably from 0.075 to 5.0%, and in particularfrom 0.1 to 3.5% by weight, based in each case on the solids of thecoating material of the invention.

[0047] The further essential constituent of the coating material of theinvention is at least one binder (A).

[0048] Examples of suitable binders (A) are random, alternating and/orblock, linear and/or branched and/or comb addition (co)polymers ofethylenically unsaturated monomers, or polyaddition resins and/orpolycondensation resins. Regarding these terms, refer for furtherdetails to Römpp, op. cit., page 457, “polyaddition” and “polyadditionresins (polyadducts)”, and also pages 463 and 464, “polycondensates”,“polycondensation” and “polycondensation resins”, and also pages 73 and74, “binders”.

[0049] Examples of suitable addition (co)polymers (A) are (meth)acrylate(co)polymers or partially saponified polyvinyl esters, in particular(meth)acrylate copolymers.

[0050] Examples of suitable polyaddition resins and/or polycondensationresins (A) are polyesters, alkyds, polyurethanes, polylactones,polycarbonates, polyethers, epoxy resin-amine adducts, polyureas,polyamides, polyimides, polyester/polyurethanes, polyether-polyurethanesor polyester-polyether-polyurethanes, especially polyesters.

[0051] Of these binders (A), the (meth)acrylate (co)polymers and thepolyesters, especially the polyesters, have particular advantages andare therefore used with particular preference.

[0052] The self-crosslinking binders (A) of the thermally curable anddual-cure coating materials of the invention contain reactive functionalgroups which are able to enter into crosslinking reactions with groupsof their kind or with complementary reactive functional groups. Theexternally crosslinking binders (A) contain reactive functional groupswhich are able to enter into crosslinking reactions with complementaryreactive functional groups which are present in crosslinking agents (E).Examples of suitable complementary reactive functional groups for use inaccordance with the invention are compiled in the following overview. Inthe overview, the variable R stands for an acyclic or cyclic aliphaticradical, an aromatic radical and/or an aromatic-aliphatic (araliphatic)radical; the variables R′ and R″ stand for identical or differentaliphatic radicals or are linked with one another to form an aliphaticor heteroaliphatic ring.

[0053] Overview: Examples of complementary functional groups Binder andcrosslinking agent or Crosslinking agent and binder —SH —C(O)—OH —NH₂—C(O)—O—C(O)— —OH —NCO —O—(CO)—NH—(CO)—NH₂ —NH—C(O)—OR —O—(CO)—NH₂—CH₂—OH >NH —CH₂—O—R —NH—CH₂—O—R —NH—CH₂—OH —N(—CH₂—O—R)₂—NH—C(O)—CH(—C(O)OR₂ —NH—C(O)—CH(—C(O)OR) (—C(O)—R) —NH—C(O)—N//R′R″>Si(OR)₂

—C(O)—OH

—C(O)—N(CH₂—CH₂—OH)₂

[0054] The selection of the respective complementary groups is guided onthe one hand by the consideration that they must not enter into anyunwanted reactions, in particular no premature crosslinking, during thepreparation, storage and application of the coating materials of theinvention, and/or, if appropriate, must not disrupt or inhibit thecuring with actinic radiation, and on the other by the temperature rangewithin which crosslinking is to take place.

[0055] In the case of the coating materials for use in accordance withthe invention, it is preferred to employ crosslinking temperatures offrom 60 to 180° C. Therefore it is preferred to employ thio, hydroxyl,N-methylolamino, N-alkoxymethylamino, imino, carbamate, allophanate,and/or carboxyl groups, preferably hydroxyl or carboxyl groups, on theone hand and, preferably, crosslinking agents containing anhydride,carboxyl, epoxy, blocked isocyanate, urethane, methylol, methylol ether,siloxane, carbonate, amino, hydroxyl and/or beta-hydroxyalkylamidegroups, preferably epoxy, beta-hydroxyalkylamide, blocked and unblockedisocyanate, urethane or alkoxymethylamino groups, on the other.

[0056] In the case of self-crosslinking coating materials of theinvention, the binders contain in particular methylol, methylol etherand/or N-alkoxymethylamino groups.

[0057] Complementary reactive functional groups which are especiallysuitable for use in the coating materials of the invention are hydroxylgroups on the one hand and blocked and unblocked isocyanate, urethane oralkoxy-methylamino groups on the other.

[0058] The functionality of the binders (A) in respect of theabove-described reactive functional groups may vary very widely and isguided in particular by the target crosslinking density and/or by thefunctionality of the particular crosslinking agent (E) employed. In thecase of hydroxyl-containing binders (A), for example, the OH number ispreferably from 15 to 300, more preferably from 20 to 250, withparticular preference from 25 to 200, with very particular preferencefrom 30 to 150, and in particular from 35 to 120, mg KOH/g.

[0059] The complementary functional groups described above may beincorporated into the binders (A) by the customary and known methods ofpolymer chemistry. This can be done, for example, by incorporatingmonomers which carry the corresponding reactive functional groups,and/or by means of polymer-analogous reactions.

[0060] Examples of suitable olefinically unsaturated monomers containingreactive functional groups are

[0061] a1) monomers which carry per molecule at least one hydroxyl,amino, alkoxymethylamino, carbamate, allophanate or imino group, such as

[0062] hydroxyalkyl esters of acrylic acid, methacrylic acid or anotheralpha,beta-olefinically unsaturated carboxylic acid which are derivedfrom an alkylene glycol which is esterified with the acid, or which areobtainable by reacting the alpha,beta-olefinically unsaturatedcarboxylic acid with an alkylene oxide such as ethylene oxide orpropylene oxide, especially hydroxyalkyl esters of acrylic acid,methacrylic acid, ethacrylic acid, crotonic acid, maleic acid, fumaricacid or itaconic acid in which the hydroxyalkyl group contains up to 20carbon atoms, such as 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl,3-hydroxybutyl, 4-hydroxybutyl acrylate, methacrylate, ethacrylate,crotonate, maleate, fumarate or itaconate; or hydroxycycloalkyl esterssuch as 1,4-bis(hydroxymethyl)cyclohexane,octahydro-4,7-methano-1H-indenedimethanol or methyl-propanediolmonoacrylate, monomethacrylate, monoethacrylate, monocrotonate,monomaleate, monofumarate or monoitaconate; reaction products of cyclicesters, such as epsilon-caprolactone, for example, and thesehydroxyalkyl or hydroxycycloalkyl esters;

[0063] olefinically unsaturated alcohols such as allyl alcohol;

[0064] polyols such as trimethylolpropane monoallyl or diallyl ether orpentaerythritol monoallyl, diallyl or triallyl ether;

[0065] reaction products of acrylic acid and/or methacrylic acid withthe glycidyl ester of an alpha-branched monocarboxylic acid having 5 to18 carbon atoms per molecule, especially a Versatic® acid, or, insteadof the reaction product, an equivalent amount of acrylic acid and/ormethacrylic acid which subsequently, during or after the polymerizationreaction, is reacted with the glycidyl ester of an alpha-branchedmonocarboxylic acid having 5 to 18 carbon atoms per molecule, especiallya Versatic® acid;

[0066] aminoethyl acrylate, aminoethyl methacrylate, allylamine orN-methyliminoethyl acrylate;

[0067] N,N-di(methoxymethyl)aminoethyl acrylate or methacrylate orN,N-di(butoxymethyl)aminopropyl acrylate or methacrylate;

[0068] (meth)acrylamides such as (meth)acrylamide, N-methyl-,N-methylol-, N,N-dimethylol-, N-methoxymethyl-, N,N-di(methoxymethyl)-,N-ethoxymethyl- and/or N,N-di(ethoxyethyl)-(meth)acrylamide;

[0069] acryloyloxy- or methacryloyloxyethyl, -propyl or -butyl carbamateor allophanate; further examples of suitable monomers containingcarbamate groups are described in the patents U.S. Pat. No. 3,479,328,U.S. Pat. No. 3,674,838, U.S. Pat. No. 4,126,747, U.S. Pat. No.4,279,833 or U.S. Pat. No. 4,340,497;

[0070] a2) monomers which carry per molecule at least one acid group,such as

[0071] acrylic acid, beta-carboxyethyl acrylate, methacrylic acid,ethacrylic acid, crotonic acid, maleic acid, fumaric acid or itaconicacid;

[0072] olefinically unsaturated sulfonic or phosphonic acids or theirpartial esters;

[0073] mono(meth)acryloyloxyethyl maleate, succinate or phthalate; or

[0074] vinylbenzoic acid (all isomers), alpha-methylvinylbenzoic acid(all isomers) or vinylbenzenesulfonic acid (all isomers);

[0075] a3) monomers containing epoxy groups, such as the glycidyl esterof acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid,maleic acid, fumaric acid or itaconic acid, or allyl glycidyl ether.

[0076] Monomers of the type described above that are of relatively highfunctionality are generally used in minor amounts. In the context of thepresent invention, minor amounts of monomers of relatively highfunctionality are those amounts which do not lead to crosslinking orgelling of the copolymers (A), especially the (meth)acrylate copolymers(A), unless the specific intention is to prepare crosslinked polymericmicroparticles.

[0077] Examples of suitable monomer units for introducing reactivefunctional groups into polyesters (A) are 2,2-dimethylolethyl- or-propylamine blocked with a ketone, the resulting ketoxime group beinghydrolyzed again after the incorporation; or compounds containing twohydroxyl groups or two primary and/or secondary amino groups and also atleast one acid group, in particular at least one carboxyl group and/orat least one sulfonic acid group, such as dihydroxypropionic acid,dihydroxysuccinic acid, dihydroxybenzoic acid, 2,2-dimethylolaceticacid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid,2,2-dimethylol-pentanoic acid, alpha,omega-diaminovaleric acid,3,4-diaminobenzoic acid, 2,4-diaminotoluenesulfonic acid or2,4-diaminodiphenyl ether sulfonic acid.

[0078] One example of introducing reactive functional groups by way ofpolymer-analogous reactions is the reaction of hydroxyl-containingresins with phosgene, resulting in resins containing chloroformategroups, and the polymer-analogous reaction of thechloroformate-functional resins with ammonia and/or primary and/orsecondary amines to give resins containing carbamate groups. Furtherexamples of suitable methods of this kind are known from the patentsU.S. Pat. No. 4,758,632 A1, U.S. Pat. No. 4,301,257 A1 or U.S. Pat. No.2,979,514 A1.

[0079] The binders (A) of the dual-cure coating materials of theinvention further contain on average per molecule at least one,preferably at least two, group(s) containing at least one bond which canbe activated with actinic radiation.

[0080] In the context of the present invention, a bond which can beactivated with actinic radiation is a bond which on exposure to actinicradiation becomes reactive and, with other activated bonds of its kind,enters into polymerization reactions and/or crosslinking reactions whichproceed in accordance with free-radical and/or ionic mechanisms.Examples of suitable bonds are carbon-hydrogen single bonds orcarbon-carbon, carbon-oxygen, carbon-nitrogen, carbon-phosphorus orcarbon-silicon single bonds or double bonds. Of these, the carbon-carbondouble bonds are particularly advantageous and are therefore used withvery particular preference in accordance with the invention. For thesake of brevity, they are referred to below as “double bonds”.

[0081] Accordingly, the group which is preferred in accordance with theinvention contains one double bond or two, three or four double bonds.If more than one double bond is used, the double bonds may beconjugated. In accordance with the invention, however, it is ofadvantage if the double bonds are present in isolation, in particulareach being present terminally, in the group in question. It is ofparticular advantage in accordance with the invention to use two doublebonds, or especially one double bond.

[0082] The dual-cure binder (A) contains on average at least one of theabove-described groups which can be activated with actinic radiation.This means that the functionality of the binder (A) in this respect isintegral, i.e., is for example two, three, four, five or more, or isnonintegral, i.e., is for example from 2.1 to 10.5 or more. The decisionas to which functionality is chosen is guided by the requirementsimposed on the particular dual-cure coating material of the invention.

[0083] If on average per molecule more than one group which can beactivated with actinic radiation is employed, the groups arestructurally different from one another or are of the same structure.

[0084] If they are structurally different from one another, this meansin the context of the present invention that use is made of two, three,four or more, but especially two, groups which can be activated withactinic radiation, which are derived from two, three, four or more, butespecially two, monomer classes.

[0085] Examples of suitable groups are (meth)acrylate, ethacrylate,crotonate, cinnamate, vinyl ether, vinyl ester, dicyclopentadienyl,norbornenyl, isoprenyl, isopropenyl, allyl or butenyl groups;dicyclopentadienyl ether, norbornenyl ether, isoprenyl ether,isopropenyl ether, allyl ether or butenyl ether groups; ordicyclopentadienyl ester, norbornenyl ester, isoprenyl ester,isopropenyl ester, allyl ester or butenyl ester groups, but especiallyacrylate groups.

[0086] Preferably, the groups are attached to the respective parentstructures of the binders (A) via urethane, urea, allophanate, ester,ether and/or amide groups, but in particular via ester groups. Normally,this occurs as a result of customary and known polymer-analogousreactions such as, for instance, the reaction of lateral glycidyl groupswith the olefinically unsaturated monomers described above that containan acid group, of lateral hydroxyl groups with the halides of thesemonomers, of hydroxyl groups with isocyanates containing double bondssuch as vinyl isocyanate, methacryloyl isocyanate and/or1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)benzene (TMI® fromCYTEC), or of isocyanate groups with the hydroxyl-containing monomersdescribed above.

[0087] However, in the dual-cure coating materials of the invention itis also possible to employ mixtures of binders (A) that are curable bymeans of heat alone and binders (A) that are curable with actinicradiation alone.

[0088] The material composition of the binders (A) does not basicallyhave any special features; rather, suitable binders (A) include

[0089] all of the binders intended for use in powder clearcoat slurriescurable thermally and/or with actinic radiation that are described inthe U.S. Pat. No. 4,268,542 A1 or U.S. Pat. No. 5,379,947 A1 and in thepatent applications DE 27 10 421 A1, DE 195 40 977 A1, DE 195 18 392 A1,DE 196 17 086 A1, DE 196 13 547 A1, DE 196 18 657 A1, DE 196 52 813 A1,DE 196 17 086 A1, DE 198 14 471 A1, DE 198 41 842 A1, DE 198 41 408 A1,DE 199 08 018 A1 or DE 199 08 013 A1 or in the European patent EP 0 652264 A1,

[0090] all of the binders intended for use in thermally curableclearcoat materials that are described in the German patent applicationDE 42 04 518 A1,

[0091] all of the binders that are intended for use in dual-cureclearcoat materials and are described in the patent applications DE 19818 735 A1, DE 198 35 296 A1, DE 197 36 083 A1, and DE 198 41 842 A1, or

[0092] all of the binders intended for use in thermally curable powderclearcoat materials that are described in the German patent applicationDE 42 22 194 A1, in the BASF Lacke+Farben AG product informationliterature “Pulverlacke”, 1990, or in the BASF Coatings AG companybrochure “Pulverlacke, Pulverlacke für industrielle Anwendungen”,January 2000.

[0093] Suitable additional binders for the dual-cure coating materialsof the invention are the binders intended for use in UV-curableclearcoat materials and powder clearcoat materials that are described inthe European patent applications EP 0 928 800 A1, EP 0 636 669 A1, EP 0410 242 A1, EP 0 783 534 A1 EP 0 650 978 A1, EP 0 650 979 A1, EP 0 650985 A1, EP 0 540 884 A1, EP 0 568 967 A1, EP 0 054 505 A1 or EP 0 002866 A1, in the German patent applications DE 197 09 467 A1, DE 42 03 278A1, DE 33 16 593 A1, DE 38 36 370 A1, DE 24 36 186 A1, and DE 20 03 579B1, in the international patent applications WO 97/46549 or WO 99/14254,or in the American patents U.S. Pat. No. 5,824,373 A1, U.S. Pat. No.4,675,234 A1, U.S. Pat. No. 4,634,602 A1, 4,424,252 A1, U.S. Pat. No.4,208,313 A1, U.S. Pat. No. 4,163,810 A1, U.S. Pat. No. 4,129,488 A1,U.S. Pat. No. 4,064,161 A1, and U.S. Pat. No. 3,974,303 A1.

[0094] The preparation of the binders (A) also has no special featuresin terms of its method but instead takes place with the aid of thecustomary and known methods of polymer chemistry, as are described, forexample, in detail in the patent documents listed above.

[0095] Further examples of suitable preparation processes for(meth)acrylate copolymers (A) are described in the European patentapplication EP 0 767 185 A1, in the German patents DE 22 14 650 B1 or DE27 49 576 B1, and in the American patents U.S. Pat. No. 4,091,048 A1,U.S. Pat. No. 3,781,379 A1, U.S. Pat. No. 5,480,493 A1, U.S. Pat. No.5,475,073 A1, and U.S. Pat. No. 5,534,598 A1, or in the standard workHouben-Weyl, Methoden der organischen Chemie, 4th edition, volume 14/1,pages 24 to 255, 1961. Suitable reactors for the copolymerizationinclude the customary and known stirred tanks, stirred tank cascades,tube reactors, loop reactors or Taylor reactors, as described forexample in the patents and patent applications DE 1 071 241 B1, EP 0 498583 A1, and DE 198 28 742 A1, or in the article by K. Kataoka inChemical Engineering Science, volume 50, No. 9, 1995, pages 1409 to1416.

[0096] The preparation of polyesters (A) is described, for example, inthe standard work Ullmanns Encyklopädie der technischen Chemie, 3rdedition, volume 14, Urban & Schwarzenberg, Munich, Berlin, 1963, pages80 to 89 and pages 99 to 105, and in the following books: “ResinesAlkydes-Polyesters” by J. Bourry, Dunod, Paris, 1952, “Alkyd Resins” byC. R. Martens, Reinhold Publishing Corporation, New York, 1961, and“Alkyd Resin Technology” by T. C. Patton, Interscience Publishers, 1962,or in the German patent application DE 42 04 518 A1.

[0097] The fraction of the binders (A) for use in accordance with theinvention in the coating materials of the invention may likewise varyextremely widely and is guided primarily by the intended use of thecoating materials. Where the coating materials of the invention arecurable thermally or both thermally and with actinic radiation, theamount is guided in particular by the functionality of the binders (A)in respect of the crosslinking reaction with the crosslinking agent (E).It is preferred to use from 10 to 80%, with particular preference from15 to 70%, and in particular from 20 to 60% by weight, based in eachcase on the solids content of the coating material of the invention.

[0098] The third essential constituent of the coating material of theinvention is at least one color and/or effect pigment (B), in particularan effect pigment (B).

[0099] Examples of suitable effect pigments are metal flake pigmentssuch as commercially customary aluminum bronzes, aluminum bronzeschromated in accordance with DE 36 36 183 A1, and commercially customarystainless steel bronzes, and also nonmetallic effect pigments, such aspearlescent pigments and interference pigments, platelet-shaped effectpigments based on iron oxide with a shade from pink to brownish red, orliquid-crystalline effect pigments. For further details, refer to Römpp,op. cit., page 176, “effect pigments” and pages 380 and 381, “metaloxide-mica pigments” to “metal pigments” and to the patent applicationsand patents DE 36 36 156 A1, DE 37 18 446 A1, DE 37 19 804 A1, DE 39 30601 A1, EP 0 068 311 A1, EP 0 264 843 A1, EP 0 265 820 A1, EP 0 283 852A1, EP 0 293 746 A1, EP 0 417 567 A1, U.S. Pat. No. 4,828,826 A, andU.S. Pat. No. 5,244,649 A.

[0100] Examples of suitable inorganic color pigments are white pigmentssuch as titanium dioxide, zinc white, zinc sulfide or lithopones; blackpigments such as carbon black, iron manganese black or spinel black;chromatic pigments such as chromium oxide, chromium oxide hydrate green,cobalt green or ultramarine green, cobalt blue, ultramarine blue ormanganese blue, ultramarine violet or cobalt violet and manganeseviolet, red iron oxide, cadmium sulfoselenide, molybdate red orultramarine red; brown iron oxide, mixed brown, spinel phases andcorundum phases or chrome orange; or yellow iron oxide, nickel titaniumyellow, chrome titanium yellow, cadmium sulfide, cadmium zinc sulfide,chrome yellow or bismuth vanadate.

[0101] Examples of suitable organic color pigments are monoazo pigments,disazo pigments, anthraquinone pigments; benzimidazole pigments,quinacridone pigments, quinophthalone pigments, diketopyrrolopyrrolepigments, dioxazine pigments, indanthrone pigments, isoindolinepigments, isoindolinone pigments, azomethine pigments, thioindigopigments, metal complex pigments, perinone pigments, perylene pigments,phthalocyanine pigments or aniline black.

[0102] For further details, refer to Römpp, op. cit., pages 180 and 181,“iron blue pigments” to “black iron oxide”, pages 451 to 453, “pigments”to “pigment volume concentration”, page 563, “thioindigo pigments”, page567, “titanium dioxide pigments”, pages 400 and 467, “naturallyoccurring pigments”, page 459, “polycyclic pigments”, page 52“azomethine pigments”, “azo pigments”, and page 379, “metal complexpigments”.

[0103] The pigments (B) may be incorporated as they are into the coatingmaterial of the invention, provided they are readily dispersed and donot agglomerate and/or their form that is responsible for the opticaleffects is not damaged or destroyed. In accordance with the invention itis of advantage if the pigments (B) are incorporated in the form ofpigment pastes. Further advantages result if the paste resins orgrinding resins used comprise binders (A) which are present in thecoating material of the invention (cf. also Römpp, op. cit., “pigmentpreparations”, page 452).

[0104] The fraction of the pigments (B) in the coating material of theinvention may vary extremely widely and is guided primarily by thehiding power of the pigments, by the desired shade and by the desiredoptical effect. The pigments (B) are preferably present in the coatingmaterial of the invention in an amount of from 0.1 to 50%, morepreferably from 0.5 to 45%, with particular preference from 0.5 to 40%,with very particular preference from 0.5 to 35%, and in particular from0.5 to 30% by weight, based in each case on the solids content of thecoating material of the invention.

[0105] Furthermore, the coating materials of the invention may comprisefluorescent, electrically conductive and/or magnetically shieldingpigments, metal powders, organic, transparent or opaque fillers and/ornanoparticles (D).

[0106] Examples of fluorescent pigments (daylight-fluorescent pigments)are bis(azomethine) pigments.

[0107] Examples of suitable electrically conductive pigments aretitanium dioxide/tin oxide pigments.

[0108] Examples of magnetically shielding pigments are pigments based oniron oxides or chromium dioxide.

[0109] Examples of suitable metal powders are powders of metals andmetal alloys, such as aluminum, zinc, copper, bronze or brass.

[0110] Examples of organic fillers are polymer powders, especially thoseof polyamide or polyacrylonitrile.

[0111] Suitable nanoparticles are selected from the group consisting ofhydrophilic and hydrophobic, especially hydrophilic, nanoparticles basedon silicon dioxide, aluminum oxide, zinc oxide and zirconium oxide andthe polyacids and heteropolyacids of transition metals, preferably ofmolybdenum and tungsten, having a primary particle size <50 nm,preferably from 5 to 50 nm, in particular from 10 to 30 nm. Thehydrophilic nanoparticles preferably have no matting effect. Particularpreference is given to using nanoparticles based on silicon dioxide.

[0112] Very particular preference is given to using hydrophilicpyrogenic silicas whose agglomerates and aggregates have a chainlikestructure and which are preparable by the flame hydrolysis of silicontetrachloride in an oxyhydrogen flame. They are sold, for example, byDegussa under the brand name Aerosil®. Very particular preference isalso given to using precipitated waterglasses, such as nanohectorites,which are sold, for example, by Südchemie under the brand name Optigel®or by Laporte under the brand name Laponite®.

[0113] Further suitable nanoparticles are described in the Americanpatent U.S. Pat. No. 4,652,470 A, column 7 line 49 to column 13 line 36.

[0114] The externally crosslinking coating materials of the inventionwhich are curable thermally, or curable thermally and with actinicradiation, comprise at least one crosslinking agent (E) which containsat least one of the above-described complementary reactive functionalgroups.

[0115] Suitable crosslinking agents (E) are known from the German patentapplication DE 199 24 171 A1, page 7 line 38 to page 8 line 47.

[0116] The coating material of the invention further comprises at leastone organic solvent (F). The solvents in question may be low-boiling andhigh-boiling (“long”) organic solvents (F). The organic solvents (F) arepreferably inert, i.e., they do not enter into any reactions with theother constituents of the coating material of the invention, unless theyare the below-listed reactive diluents (G) curable thermally or withactinic radiation. The organic solvents are preferably selected from thesolvents described in D. Stoye and W. Freitag (editors), “Paints,Coatings and Solvents”, second, completely revised edition, Wiley-VCH,Weinheim, New York, 1998, “14.9 Solvent Groups”, pages 327 to 373.

[0117] The coating material of the invention may further comprise atleast one typical coatings additive (G).

[0118] Examples of suitable additives (G) are molecularly disperselysoluble dyes; light stabilizers, such as UV absorbers and reversiblefree-radical scavengers (HALS); antioxidants; devolatilizers; wettingagents; emulsifiers; slip additives; polymerization inhibitors; thermalcrosslinking catalysts; thermolabile free-radical initiators;photoinitiators and photocoinitiators; thermally curable reactivediluents; reactive diluents curable with actinic radiation; binderscurable with actinic radiation; adhesion promoters; leveling agents;film formation auxiliaries; rheological aids (thickeners and/or sagcontrol agents); flame retardants; corrosion inhibitors; free-flow aids;waxes; siccatives; biocides and/or flatting agents; such as aredescribed in detail, for example, in the textbook “Lackadditive”[Additives for Coatings] by Johan Bieleman, Wiley-VCH, Weinheim, NewYork, 1998, and in the German patent application DE 199 14 896 A1,column 14 line 26 to column 15 line 46. For further details, refer to DE199 04 317 A1 and DE 198 55 125 A1.

[0119] The coating material of the invention, especially the basecoatmaterial of the invention, is outstandingly suitable for the productionof multicoat color and/or effect paint systems on primed and unprimedsubstrates by the wet-on-wet technique. Furthermore, the coatingmaterial of the invention, especially the solid-color topcoat materialof the invention, is outstandingly suitable for the production ofsingle-coat color and/or effect paint systems.

[0120] Otherwise, the coating material of the invention may also be usedas an adhesive or sealing compound or as a starting product for thepreparation of self-supporting paint films.

[0121] Particular advantages are displayed by the coating material ofthe invention in its use as a basecoat material in the context of thewet-on-wet technique, in which the basecoat material is applied to theprimed or unprimed substrate and flashed off and/or dried, but notcured, and then the basecoat film is overcoated with a clearcoatmaterial and the resultant clearcoat film is cured together with theaqueous basecoat film, thermally or both thermally and with actinicradiation (dual cure).

[0122] Suitable coating substrates are all surfaces which are notdamaged by curing of the films present thereon using heat or using acombination of heat and actinic radiation (dual cure); examples includemetals, plastics, wood, ceramic, stone, textile, fiber composites,leather, glass, glass fibers, glasswool and rockwool, mineral- andresin-bound building materials, such as plasterboard panels and cementslabs or roof tiles, and also composites of these materials.

[0123] In the case of electrically conductive substrates it is possibleto use primers which are produced in a customary and known manner fromelectrodeposition coating materials (electrocoat materials). Both anodicand cathodic electrocoat materials are suitable for this purpose, butespecially cathodic. Usually, and especially in automotive finishing,the electrocoat is overcoated with a primer-surfacer coat orantistonechip primer coat, which may be regarded as part of the primersystem.

[0124] It is also possible to coat, bond or seal primed or unprimedplastics parts made, for example, of ABS, AMMA, ASA, CA, CAB, EP, UF,CF, MF, MPF, PF, PAN, PA, PE, HDPE, LDPE, LLDPE, UHMWPE, PC, PC/PBT,PC/PA, PET, PMMA, PP, PS, SB, PUR, PVC, RF, SAN, PBT, PPE, POM, PUR-RIM,SMC, BMC, PP-EPDM and UP (abbreviated codes in accordance with DIN7728T1). Unfunctionalized and/or nonpolar substrate surfaces may besubjected prior to coating in a known manner to a pretreatment, such aswith a plasma or by flaming, or may provided with a water-based primer.

[0125] Accordingly, the coating materials of the invention areoutstandingly suitable for the coating of motor vehicle bodies, parts ofmotor vehicle bodies, the interior and exterior of motor vehicles,buildings inside and out, doors, windows and furniture, and for coatingin the context of industrial coating of, for example, small parts, suchas nuts, bolts, wheel rims or hubcaps, coils, containers, packaging,electrical components, such as motor windings or transformer windings,and white goods, such as domestic appliances, boilers and radiators.

[0126] In the context of automotive finishing, the coating materials ofthe invention are of outstanding suitability for the production oforiginal finishes (OEM) and refinishes.

[0127] The coating materials of the invention may be applied by any ofthe customary application methods, such as spraying, knife coating,brushing, flow coating, dipping, impregnating, trickling or rolling, forexample. The substrate to be coated may itself be at rest, with theapplication device or unit being moved. Alternatively, the substrate tobe coated, particularly a coil, may be moved, with the application unitbeing at rest relative to the substrate or being moved appropriately.

[0128] It is preferred to employ spray application methods, such ascompressed air spraying, airless spraying, high-speed rotation,electrostatic spray application (ESTA), alone or in conjunction withhotspray application such as hot air spraying, for example. Applicationmay be made at temperatures of max. 70 to 80° C., so that suitableapplication viscosities are achieved without any change in or damage tothe basecoat material and its overspray (which may be intended forreprocessing) during the short period of thermal loading. For instance,hotspraying may be configured in such a way that the basecoat materialis heated only very shortly in the spray nozzle or shortly before thespray nozzle.

[0129] It is particularly advantageous to apply the basecoat material ofthe invention by ESTA in a first application and to apply a secondapplication pneumatically.

[0130] Where the basecoat materials of the invention includeconstituents which can be activated with actinic radiation, applicationis preferably carried out in the absence of light. These applicationmethods may of course be used for the application of the clearcoat aswell in the context of the wet-on-wet technique of the invention.

[0131] Curing may take place after a certain rest period. This periodmay have a duration of from 30 s to 2 h, preferably from 1 min to 1 h,and in particular from 1 min to 45 min. The rest period is used forexample, for leveling and devolatilization of the paint films or for theevaporation of volatile constituents such as solvents. The rest periodmay be assisted and/or shortened by the use of elevated temperatures upto 90° C. and/or by a reduced air humidity <10 g water/kg air,especially <5 g/kg air, provided this does not entail any damage to orchange in the paint films, such as premature complete crosslinking, forinstance.

[0132] Physical curing takes place during the rest period and may beaccelerated by the application of heat, it being possible to employ themethods used below in the context of the thermal cure.

[0133] The thermal cure has no special features as far as this method isconcerned, but is instead carried out in accordance with the customaryand known methods such as heating in a forced air oven or exposure to IRlamps. The thermal cure may also take place in stages. The thermal curetakes place advantageously at a temperature of from 50 to 100° C., withparticular preference from 60 to 100° C., and in particular from 80 to100° C., for a period of from 1 min up to 2 h, with particularpreference from 2 min up to 1 h, and in particular from 3 min to 45 min.Where substrates are used which have high thermal load-bearingcapacities, the thermal crosslinking may also be carried out attemperatures above 100° C. In this case it is generally advisable not toexceed temperatures of 180° C., preferably 160° C., and in particular155° C.

[0134] The actinic radiation cure also has no special features as far asthis method is concerned, but instead takes place in a customary andknown manner by irradiation with UV lamps and/or electron beam sources,preferably under inert gas, as is described, for example, in the Germanpatent application DE 198 18 735 A1, column 10 lines 31 to 61.

[0135] In the case of conjoint curing of the dual-cure basecoat films ofthe invention with the clearcoat films, the thermal cure and actinicradiation cure may be employed simultaneously or alternately. Where thetwo curing methods are used alternately, it is possible, for example, tocommence with the thermal cure and to end with the actinic radiationcure. In other cases it may prove advantageous to begin and to end withthe actinic radiation cure. The skilled worker is able to determine thecuring method most advantageous for the case in hand on the basis of hisor her general knowledge in the art, possibly with the assistance ofsimple preliminary tests. For further details, refer to the Germanpatent application DE 198 18 735 A1, column 10 line 31 to column 11 line33.

[0136] In this context it is found to be a further particular advantageof the basecoat material of the invention that all of the customary andknown clearcoat materials may be combined with the basecoat film of theinvention in the context of the wet-on-wet technique.

[0137] Clearcoat materials known per se are one-component ormulticomponent clearcoat materials, powder clearcoat materials, powderslurry clearcoat materials, UV-curable clearcoat materials or sealers,as are known from the patent applications, patents and publications DE42 04 518 A1, EP 0 594 068 A1, EP 0 594 071 A1, EP 0 594 142 A1, EP 0604 992 A1, EP 0 596 460 A1, WO 94/10211, WO 94/10212, WO 94/0213, WO94/22969 or WO 92/22615, U.S. Pat. No. 5,474,811 A1, U.S. Pat. No.5,356,669 A1 or U.S. Pat. No. 5,605,965 A1, DE 42 22 194 A1, the BASFLacke+Farben AG product information literature “Pulverlacke”, 1990, theBASF Coatings AG brochure “Pulverlacke, Pulverlacke für industrielleAnwendungen”, January 2000, U.S. Pat. No. 4,268,542 A1, DE 195 40 977A1, DE 195 18 392 A1, DE 196 17 086 A1, DE-A-196 13 547, DE 196 52 813A1, DE-A-198 14 471 A1, EP 0 928 800 A1, EP 0 636 669 A1, EP 0 410 242A1, EP 0 783 534 A1, EP 0 650 978 A1, EP 0 650 979 A1, EP 0 650 985 A1,EP 0 540 884 A1, EP 0 568 967 A1, EP 0 054 505 A1, EP 0 002 866 A1, DE197 09 467 A1, DE 42 03 278 A1, DE 33 16 593 A1, DE 38 36 370 A1, DE 2436 186 A1, DE 20 03 579 B1, WO 97/46549, WO 99/14254, U.S. Pat. No.5,824,373 A1, U.S. Pat. No. 4,675,234 A1, U.S. Pat. No. 4,634,602 A1,U.S. Pat. No. 4,424,252 A1, U.S. Pat. No. 4,208,313 A1, U.S. Pat. No.4,163,810 A1, U.S. Pat. No. 4,129,488 A1, U.S. Pat. No. 4,064,161 A1,U.S. Pat. No. 3,974,303 A1, EP 0 844 286 A1, DE 43 03 570 A1, DE 34 07087 A1, DE 40 11 045 A1, DE 40 25 215 A1, DE 38 28 098 A1, DE 40 20 316A1 and DE 41 22 743 A1.

[0138] Within the multicoat paint system of the invention the thicknessof the individual coats may vary widely. In accordance with theinvention it is of advantage, however, if the basecoat has a thicknessof from 5 to 25 μm, in particular from 7 to 20 μm, and the clearcoat hasa thickness of from 15 to 120 μm, preferably from 30 to 80 μn and inparticular from 40 to 70 μm.

[0139] The single-coat and multicoat paint systems of the invention haveoutstanding optical, mechanical, and chemical properties. For instance,they are free from any surface defects such as shrinkage (wrinkling).Moreover, they have a particularly high hiding power and outstandingoptical effects, especially cloud-free metallic effects.

[0140] Moreover, in the course of refinishing using the coatingmaterials of the invention, differences in shade between the originalfinish and the refinish, if they are present at all, are only veryslight, and acceptable, if one and the same basecoat material of theinvention is used.

INVENTIVE AND COMPARATIVE EXAMPLES Preparation Example 1

[0141] The Preparation of a Silicon Dioxide Paste for Inventive use

[0142] 75 parts by weight of a commercially customary, branchedpolyester resin suitable for basecoat materials and having a solidscontent of 60% by weight (solvent: Solventnaphtha®/butyl acetate 1:1)and an OH number of 80 mg KOH/g, 10 parts by weight of a silicon dioxidepowder with an average particle size of 5.8 μm and a density of 2.5g/cm⁻³ and 15 parts by weight of butyl glycol acetate were mixed withone another and homogenized.

Preparation Example 2

[0143] The Preparation of the Solution of a Film Formation Auxiliary

[0144] 15 parts by weight of a cellulose ester from Eastman with anacetyl content of 16% by weight and a butyrate content of 33-38.9% byweight, based on the cellulose ester, were dissolved in 75 parts byweight of a mixture of butyl acetate and isotridecyl alcohol in a weightratio of 23:1.

Preparation Example 3

[0145] The Preparation of a Paste of an Aluminum Effect Pigment

[0146] The paste was prepared from 33 parts by weight of an aluminumeffect pigment, 33 parts by weight of a mixture comprising, based on themixture, 37.5% by weight of a 6 percent dispersion of a modifiedpolyethylene wax in butyl acetate/Solventnaphtha®, 12.5% by weight ofbutyl acetate and 50% by weight of a solution of the film formationauxiliary from preparation example 2, and 33 parts by weight of butylacetate

Inventive Example 1

[0147] The Preparation of an Inventive Basecoat Material

[0148] The inventive basecoat material was prepared by mixing thefollowing constituents in the stated order and homogenizing theresulting mixture:

[0149] 225 parts by weight of a 6′ percent dispersion of a modifiedpolyethylene wax in butyl acetate/Solventnaphtha®,

[0150] 183 parts by weight of the film formation auxiliary frompreparation example 2,

[0151] 126 parts by weight of a commercially customary, branchedpolyester resin suitable for basecoat materials and having a solidscontent of 0.60% by weight (solvent: Solventnaphtha®/butyl acetate 1:1)and an OH-number of 80 mg KOH/g,

[0152] 63 parts by weight of a pseudoplastic polyester (Setal® 90173from Akzo),

[0153] 126 parts by weight of a solution of a medium-reactivity melaminresin partially etherified with butanol (55 percent in butanol),

[0154] 24 parts by weight of an epoxidized fatty acid ester,

[0155] 14 parts by weight of butyl acetate,

[0156] 13 parts by weight of butanol,

[0157] 55 parts by weight of butyl glycol acetate,

[0158] 1.3 parts by weight of a commercial coatings additive (Byk® 410from Byk Chemie),

[0159] 5 parts by weight of a silicone-free leveling agent based on anamino-resin-modified methacrylate copolymer,

[0160] 20 parts by weight of the silicon dioxide paste from preparationexample 1,

[0161] 90 parts by weight of the paste of an aluminum effect pigmentfrom preparation example 3, and

[0162] 75 parts by weight of butyl acetate.

[0163] The basecoat material had a viscosity of 23 seconds in the DIN4flow cup. For application, the basecoat material was adjusted with 290parts by weight of butyl acetate to a spray viscosity of 26 seconds inthe ISO4 flow cup.

Comparative Example C1

[0164] Preparation of a Noninventive Basecoat Material

[0165] Example 1 was repeated except that the silicon dioxide paste frompreparation example 1, for use in accordance with the invention, was notused. The polyester fraction and the solvent fraction introduced intothe basecoat material 1 of inventive example 1 by the silicon dioxidepaste was compensated in the present comparative example by the additionof polyester and solvent.

Inventive Example 2 and Comparative Example C2

[0166] The production of an Inventive (Inventive Example 2) and of aNoninventive (Comparative Example C2) Multicoat Paint System

[0167] For inventive example 2, the basecoat material 1 from inventiveexample 1 was used.

[0168] For comparative example C2, the basecoat material C1 fromcomparative example C1 was used.

[0169] For the testing of the performance properties of the basecoatmaterials 1 and C1, test panels measuring 30×70 cm were produced in acustomary and known manner. This was done by coating steel panels(bodywork panels), which had been coated with a customary and known,cathodically deposited and baked electrocoat, with a commercialprimer-surfacer from BASF Coatings AG), after which the resultingprimer-surfacer films were flashed off at 20° C. and a relativeatmospheric humidity of 65% for 5 minutes and baked in a forced air ovenat 140° C. for 30 minutes.

[0170] After the test panels were cooled to 20° C., in a first seriesthe basecoat materials 1 and C1 were applied in a wedge pneumaticallyusing an automated sprayer. The basecoat films were then flashed off for5 minutes and overcoated with a commercial two-component clearcoatmaterial (BASF Coatings AG). Thereafter the basecoat films and theclearcoat films were baked at 130° C. for 30 minutes, so giving theinventive multicoat effect system of inventive example 2 and thenoninventive multicoat system of comparative example C2.

[0171] The shade stability of the multicoat systems as a function of thethickness of the basecoats was determined with the aid of the methoddescribed in the German patent application DE 197 09 406 A1 or theEuropean patent EP 0 842 414 B1. The shade of the inventive multicoatsystem from inventive example 2 was found to be stable, whereas this wasnot the case with the noninventive multicoat system from comparativeexample C2.

[0172] The first series was repeated, except that the basecoat filmswere applied hidingly in a uniform film thickness.

[0173] The test panels were assessed visually for light-dark shading(clouds) under diffuse light from a distance of from 2 to 3 m, straighton (80°) and obliquely (40°), and were rated accordingly (rating 1: noclouds visible; to rating 5: clouds very distinctly visible).

[0174] For inventive example 2, the rating was 1 for both straight-onand oblique viewing. For comparative example C2, the ratings were 4 whenviewed straight on and 5 when viewed obliquely. This underscored thefact that the inventive use of the silicon dioxide enabled a significantimprovement to be achieved in the light-dark shading.

Inventive Example 3 and Comparative Example C3

[0175] The production of an Inventive (Inventive Example 3) and of aNoninventive (Comparative Example C3) Refinish System

[0176] For inventive example 3, the basecoat material 1 from inventiveexample 1 was used.

[0177] For the comparative experiment C3, the basecoat material C1 fromcomparative example C1 was used.

[0178] For the testing of the performance properties of the basecoatmaterials 1 and C1 in automotive refinish, test panels measuring 30×70cm were produced in a customary and known manner. This was done bycoating steel panels (bodywork panels), which had been coated with acustomary and known, cathodically deposited and baked electrocoat, witha commercial primer-surfacer from BASF Coatings AG), after which theresulting primer-surfacer films were flashed off at 20° C. and arelative atmospheric humidity of 65% for 5 minutes and baked in a forcedair oven at 140° C. for 30 minutes.

[0179] After the test panels were cooled to 20° C., the basecoatmaterials 1 and C1 were applied hidingly, 60% electrostatically using anESTA high-speed rotary bell, and 40% pneumatically. The basecoat filmswere then flashed off for 5 minutes and overcoated with a commercialtwo-component clearcoat material (BASF Coatings AG). Thereafter thebasecoat films and the clearcoat films were baked at 130° C. for 30minutes.

[0180] After the test panels had cooled to room temperature, half oftheir coated surfaces was covered.

[0181] In order to simulate a refinish, the uncovered halves of the testpanels bearing the noninventive multicoat paint system were provided, asdescribed above, with a further inventive multicoat paint system(inventive example 3), but the basecoat material was appliedpneumatically.

[0182] In order to simulate a refinish, the uncovered halves of the testpanels bearing the noninventive multicoat paint system were provided, asdescribed above, with a further noninventive multicoat paint system(comparative example C3), and here again the basecoat material wasapplied pneumatically.

[0183] The difference in shade between the original finishes and therefinishes was determined by colorimetry and rated as follows:

[0184] rating 1, no deviation;

[0185] rating 2, slight deviation, still acceptable;

[0186] rating 3, moderate deviation;

[0187] rating 4, already clearly visible deviation; and

[0188] rating 5, severe deviation.

[0189] The inventive refinish of inventive example 3 received the rating2; the noninventive refinish of comparative example C3 received therating 5.

What is claimed is:
 1. A solventborne coating material curablephysically, thermally, or thermally and with actinic radiation,comprising A) at least one binder curable physically, thermally orthermally and with actinic radiation, B) at least one color and/oreffect pigment, and C) at least one colorless, transparent or opaquepowder which is substantially inert with respect to the otherconstituents of the coating material and whose particles have an averagesize of from 1.0 to 10.0 μm and a density of from 1.25 to 3.6 g cm⁻³. 2.The solventborne coating material as claimed in claim 1, wherein thepowder (C) has an average particle size of from 4.0 to 7.0 μm.
 3. Thesolventborne coating material as claimed in claim 1 or 2, wherein theparticles have a density of from 1.4 to 3.0 g cm⁻³.
 4. The solventbornecoating material as claimed in any of claims 1 to 3, wherein theparticles have a spherical shape.
 5. The solventborne coating materialas claimed in any of claims 1 to 4, wherein the powder (C) has a maximumparticle size of below 12 μm.
 6. The solventborne coating material asclaimed in any of claims 1 to 5, wherein the particles are ofcrosslinked or uncrosslinked, organic or organometallic polymers,inorganic minerals, salts or ceramic materials, or organically modifiedceramic materials, or mixtures of these substances.
 7. The solventbornecoating material as claimed in any of claims 1 to 6, wherein theparticles are of silicon dioxide, aluminum silicates, calcium silicates,magnesium silicates, calcium aluminum silicates, magnesium aluminumsilicates, calcium magnesium silicates, calcium magnesium aluminumsilicates, beryllium aluminum silicates, aluminum phosphate and/orcalcium phosphate.
 8. The solventborne coating material as claimed inany of claims 1 to 7, comprising the powder (C) in an amount of from0.05 to 7.0% by weight, based on the solids content.
 9. The use of thesolventborne coating material as claimed in any of claims 1 to 8 forproducing single-coat or multicoat color and/or effect paint systems forautomotive OEM finishing and automotive refinish, for industrialcoating, including coil coating and container coating, for the coatingof plastics, and for furniture coating.
 10. The use as claimed in claim9, wherein the solventborne coating material is used as basecoatmaterial and solid-color topcoat material in automotive OEM finishingand automotive refinish.
 11. A process for producing a single-coat ormulticoat color and/or effect paint system by applying at least one filmof the solventborne coating material as claimed in any of claims 1 to 8to a primed or unprimed substrate and subjecting the resulting wetfilm(s) to thermal curing or curing with heat and actinic light.
 12. Aprocess for producing a multicoat color and/or effect paint system bythe wet-on-wet technique, by (I) applying a basecoat film to a primed orunprimed substrate, (II) flashing off and/or initially drying theresulting basecoat film, (III) applying a clearcoat film to the basecoatfilm, and (V) subjecting the two wet films to thermal curing or tothermal curing and curing with actinic radiation, which comprises usingas basecoat material the solventborne coating material as claimed in anyof claims 1 to 8.